1. Technical Field
This invention relates to methods, computer program products, information servers, information sources and a system in the context of pulling information from information sources, and in particular in the context of pulling presence information from presence sources.
2. Discussion of Related Art
Presence information may be understood as a status indicator that expresses an ability and/or willingness of a potential communication partner, for instance a user of a computer or telecommunications network, to communicate. Presence information is provided by presence sources, for instance specific agents in a user's client, to a presence service. In this context, a so-called presentity (a combination of the words “presence” and “entity”) is understood as an entity that has presence information associated with it, wherein said presence information may be composed from a multitude of presence sources. A presentity may for instance be a person, although it might also represent a “help desk”, or a resource such as a meeting room, to give but a few examples. A presence server accepts, stores and distributes presence information. A watcher is understood as an entity that requests presence information about a presentity from the presence service. A watcher may for instance be a person that wants to communicate with another person (the presentity) and thus requires presence information on this presentity.
Using presence information is a growing tool towards more effective and efficient communication within a business setting, since it allows (a watcher) to instantly see who (the one or more presentities) is for instance available in a corporate network for a short-term meeting or a conference call.
In document “Presence SIMPLE Specification”, Draft Version 2.0, 19 Feb. 2007, by Open Mobile Alliance (OMA), which document is incorporated herein by reference, an application-level specification for the OMA Session Initiation Protocol (SIP)/SIP Instant Message and Presence Leveraging Extensions (SIMPLE) presence service is defined.
For this presence service, it is desired that the presence service supports the pulling (retrieval) of presence information from presence sources (e.g. network entities, user agents, etc.) either ad-hoc or on a periodic basis. Furthermore, it is desired that watchers may be able to request the presence server to pull presence information from presence sources.